MAX7221CNG
Overview
The MAX7221CNG is a compact, serial input/output common-cathode display driver that interfaces microprocessors to 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. It features an on-chip BCD code-B decoder, multiplex scan circuitry, segment and digit drivers, and an 8x8 static RAM that stores each digit. The device is specifically designed with slew-rate limited segment drivers to reduce electromagnetic interference (EMI) in sensitive environments.
Why Choose This Part
The MAX7221 is compatible with SPI, QSPI, and MICROWIRE interfaces and features a 150uA low-power shutdown mode that retains data. Its slew-rate limited segment drivers significantly reduce radiated EMI compared to the standard MAX7219, making it ideal for precision analog environments. The 24-pin DIP package is highly popular for through-hole prototyping and educational projects.
Applications
Getting Started
To begin development, connect the 3-wire serial interface (DIN, CLK, LOAD) to your microcontroller and place a single external resistor (RSET) between the V+ and ISET pins to set the peak segment current. Ensure a 10uF electrolytic and 0.1uF ceramic capacitor are placed close to the V+ pin to manage switching transients. Standard Arduino and peripheral libraries for the MAX7219/MAX7221 family are widely available to simplify register configuration.
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